Analysis: Sanders' mistake was not declaring victory after he already won

Among pledged delegates, she bested him by a 55 percent-to-45 percent margin; in the popular vote, it was 56 percent to 43 percent; and among all delegates, it was 60 percent to 40 percent.

But there are still two ways in which Sanders succeeded. One, he performed better than anyone - probably including himself - ever expected, giving Clinton a truly competitive race.

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NEW YORK, NEW YORK - APRIL 13: Attendees await the start of a campaign event for Democratic presidential candidate U.S. Senator Bernie Sanders (not pictured) at Washington Square Park on April 13, 2016 in New York City. (Photo by D Dipasupil/WireImage)

NEW YORK, NEW YORK - APRIL 13: Attendees await the start of a campaign event for Democratic presidential candidate U.S. Senator Bernie Sanders (not pictured) at Washington Square Park on April 13, 2016 in New York City. (Photo by D Dipasupil/WireImage)

Attendees hold signs in support of Senator Bernie Sanders, an independent from Vermont and 2016 Democratic presidential candidate, not pictured, at a campaign event in New York, U.S., on Wednesday, April 13, 2016. Sanders stepped up his feud with General Electric Co., denouncing the manufacturer as 'greedy' and accusing Chief Executive Officer Jeffrey Immelt of not being truthful in responding to the attacks. Photographer: Victor J. Blue/Bloomberg via Getty Images

Natalia Plaza (L) and Suzanne Tufan, with their faces painted, wait for a campaign rally with U.S. Democratic presidential candidate and U.S. Senator Bernie Sanders in Washington Square Park in the Greenwich Village neighborhood of New York, New York April 13, 2016. REUTERS/Brian Snyder

An attendee wears a t-shirt in support of Senator Bernie Sanders, an independent from Vermont and 2016 Democratic presidential candidate, not pictured, at a campaign event in New York, U.S., on Wednesday, April 13, 2016. Sanders stepped up his feud with General Electric Co., denouncing the manufacturer as 'greedy' and accusing Chief Executive Officer Jeffrey Immelt of not being truthful in responding to the attacks. Photographer: Victor J. Blue/Bloomberg via Getty Images

An attendee holds a sign in support of Senator Bernie Sanders, an independent from Vermont and 2016 Democratic presidential candidate, not pictured, at a campaign event in New York, U.S., on Wednesday, April 13, 2016. Sanders stepped up his feud with General Electric Co., denouncing the manufacturer as 'greedy' and accusing Chief Executive Officer Jeffrey Immelt of not being truthful in responding to the attacks. Photographer: Victor J. Blue/Bloomberg via Getty Images

NEW YORK, NEW YORK - APRIL 13: Rosario Dawson speaks onstage at a campaign event for Democratic presidential candidate U.S. Senator Bernie Sanders (not pictured) at Washington Square Park on April 13, 2016 in New York City. (Photo by D Dipasupil/WireImage)

NEW YORK, NY - APRIL 13: Film director Spike Lee attends the Bernie Sanders rally in Washington Square Park on April 13, 2016 in New York City. (Photo by Mireya Acierto/FilmMagic)

U.S. Democratic presidential candidate Bernie Sanders addresses supporters at his campaign rally in Washington Square Park in the Greenwich Village neighborhood of New York City, April 13, 2016. REUTERS/Brendan McDermid

U.S. Democratic presidential candidate Bernie Sanders addresses supporters at his campaign rally in Washington Square Park in the Greenwich Village neighborhood of New York City, April 13, 2016. REUTERS/Brian Snyder

Yet after those victories, after the final primary results and after Clinton became the party's presumptive presidential nominee, Sanders still marches on. He hasn't conceded to Clinton or endorsed her. And on Tuesday, Sanders made a series of demands, including:

New leadership inside the Democratic National Committee (presumably replacing DNC Chair Debbie Wasserman Schultz);
The most progressive Democratic platform in history;
More open primaries;
And eliminating superdelegates in the Democratic nominating system.

But the demands on DNC leadership, open primaries and superdelegates seem small. Why call for reforms to processes that you and your supporters deem unfair (rightly or wrongly), while not touching other processes (the caucuses) that benefited you?

Not conceding to Clinton appears even smaller, especially after she became the first female to become the presumptive presidential nominee of a major political party.

And the leverage he has seems even smaller still, given that Clinton won eight of the last 11 Democratic contests; that President Barack Obama and Sen. Elizabeth Warren already endorsed Clinton; and that polls show Clinton expanding her lead over Donald Trump - all suggesting that Clinton might not need Sanders' blessing to win the White House.

On Tuesday - after he issued his list of demands - Sanders met with Clinton. And their campaigns both released positive-sounding statements about the meeting.

"Sanders congratulated Secretary Clinton on the campaign she has run and said he appreciated her strong commitment to stopping Trump in the general election," the Sanders campaign's statement read. "The two discussed a variety of issues where they are seeking common ground: substantially raising the minimum wage; real campaign finance reform: making health care universal and accessible; making college affordable and reducing student debt."

The statement concluded, "Sanders and Clinton agreed to continue working to develop a progressive agenda that addresses the needs of working families and the middle class and adopting a progressive platform for the Democratic National Convention." (Note: While the Clinton campaign's statement called for unity, Sanders' made no mention of the "U" word.)

Bottom line: Sanders' campaign - in one way or another - continues.

But whether it's in politics or at the gambling table, there's a risk when you stay too long, especially after you've already won.